U.S. Pat. Nos. 4,093,430 and 4,110,086 (collectively the Schwab et al references) disclose a method for removing contaminants from exhaust gas streams and, in particular, fine particle emissions. The Schwab et al reference teaches that exposing the exhaust gases to a high energy, extremely dense electrostatic field serves to charge contaminants in the exhaust gas stream, which can then be collected. Water was introduced into the exhaust gas stream as an added wet scrubbing medium to assist with collection of contaminants. The Schwab et al references reported collection efficiency of approximately 95% of 0.5 micron sized contaminants and 97.5% of 1.25 micron sized contaminants. At these efficiency levels the system consumed about 6 gpm/1000 acfm of water, 150 watts/1000 acfm charging unit power and experienced 6 inches of water pressure drop.
Although the teachings of the Schwab et al references demonstrate promising results in terms of the ability to capture a high percentage of fine particulate emissions, the energy costs in doing so are unacceptably high.